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Vascular Biology Research

UChicago_DSCN0496
(The University of Chicago - Maya Lim)
 
 

- Vascular System and Vascular Biology

The vascular system involves the heart and blood vessels. The blood vessels include arteries, which are tubes that transport blood from your heart to the rest of your body, and veins, which return the blood to your heart. This complex system is involved in many diverse functions, but the most important is transporting vital oxygen and nutrients to your tissues and organs.  
  • Arteries are thicker and are prone to developing blockages or dilations. 
  • VEINS Veins are thinner and have valves that keep the blood moving back toward the heart. The larger deep veins of the legs can develop clots.

 

Blood vessels are composed of three layers:

  • The inner layer (intima) is lined by specialized cells called endothelial cells. One of the main functions of this lining is to keep the vessels from clotting.
  • The middle layer (media) is composed of muscle cells, and allows the vessels to expand and contract.
  • The outer layer (adventitia) provides strength so vessels do not burst under pressure.
 

Vascular disease is a class of diseases of the blood vessels – the arteries and veins of the circulatory system of the body. It is a subgroup of cardiovascular disease. Disorders in this vast network of blood vessels, can cause a range of health problems which can be severe or prove fatal.

It is an interesting endeavor to review progress in a field that did not exist 50 years ago in the present context of the term - vascular biology. Certainly, in 1950, there was basic understanding of the role of arteries and veins in cardiovascular physiology and of capillaries in gas and nutrient transport. Furthermore, there was considerable clinical knowledge about the role of atherosclerosis in ischemia and infarction of the heart and other organs and that of hypertension in inducing microvascular damage and organ failure, particularly in the kidney. 

Vascular biology, which connotes the study of the biology of the constituent cells of the normal and diseased vascular wall, first gained some currency in the 1970s in defining this new field of study, which has enjoyed explosive growth in the past 25 years. 

 

- Diseases of The Vascular System

Diseases of the vascular system can be life-threatening or can severely decrease your quality of life. Vascular biology helps scientists and vascular surgeons and other physicians understand the causes of vascular diseases. With this knowledge, new and better methods to prevent and treat these diseases become possible. 

In general, diseases of the blood vessels (particularly the arteries) involve either blockage, usually due to atherosclerosis (hardening of the arteries), or degeneration (weakening of the wall) resulting in aneurysm. Common diseases include: 

  • CAROTID ATHEROSCLEROSIS involves blockage of the arteries that supply the brain with blood. When these arteries become diseased, a stroke (brain damage) may result.
  • AORTIC ANEURYSM involves degeneration of the main blood vessel within the body, the aorta. When the wall of the aorta weakens, it starts to dilate. Rupture of the aorta in this circumstance can lead to death.
  • PERIPHERAL ARTERIAL DISEASE involves blockage of the arteries that supply the legs with blood. When these arteries become diseased, the person may be unable to walk without pain, or may even lose his/her limbs.

 

- Vascular Biology Research and Medicine

Vascular biology research can lead to the prevention of the diseases that are the leading causes of death in Western cultures, including heart attack and stroke. This research is very costly to perform but can lead to significant improvement in lifespan and quality of life.

Scientists hope to learn effective methods for preventing leading vascular diseases like atherosclerosis. This would lead to fewer strokes and heart attacks (the result of blocked heart arteries), and preservation of the function of our legs. Atherosclerosis is a very complex disease that results from smoking, diabetes, cholesterol and high blood pressure. Controlling these risk factors, however, is not enough to prevent such a devastating disease and future research is critical for cures in this area. 

Similarly, a better understanding the nature of aortic aneurysm will help prevent deaths from rupture of the aorta. Degradation of the wall of the aorta that results in aneurysm formation is also a very complex process that can be related to smoking, high blood pressure and atherosclerosis. Current treatments involve replacement of the aorta. With more knowledge of the disease process, however, scientists may learn how to prevent the problem altogether.

In the decades to follow, research in vascular biology predominantly targeted 3 facets of vascular function: vasomotor tone, inflammation, and the balance between thrombosis and thrombolysis. This occurred because atherosclerotic cardiovascular disease reached epidemic levels and atherothrombosis was found to feature disturbances in these functions that preceded visible pathology and clinical manifestations of the disease. Furthermore, modification of responsible causal factors reversed impaired vascular function (eg, lowering levels of low-density lipoproteins in atherosclerosis), and clinical studies began to validate the importance of preclinical vascular biology research in the treatment of hypertension, atherosclerosis, pulmonary vascular disease, erectile dysfunction, Raynaud phenomenon, and neointimal proliferation after mechanical vascular intervention. 

More recently, advances in molecular biology and –omics technologies have facilitated in vitro and in vivo studies that revealed that blood vessels regulate their own redox milieu, metabolism, mechanical environment, and phenotype, in part, through complex interactions between cellular components of the blood vessel wall and circulating factors. These interactors include stem, progenitor, and differentiated cells; microRNAs, long noncoding RNAs, and DNA; and, hormones, proteins, and lipids. Dysregulation of these carefully orchestrated homeostatic interactions has also been implicated as the mechanism by which risk factors for cardiopulmonary vascular disease lead to vascular dysfunction, structural remodeling, and, ultimately, adverse clinical events, including myocardial infarction, stroke, critical limb ischemia, and pulmonary hypertension.

 

- The Future of Vascular Biology

Much research has been dedicated to describing the exact changes within our arteries that result in atherosclerosis and aneurysm. Looking forward, research will focus on understanding:  

  • How genetics make us prone to these diseases.
  • How stem cells, those cells in our bodies that are responsible for regenerating tissues, help repair degenerating arteries.

 

With a full understanding of these unique processes, scientists and physicians will not only find ways to prevent and treat these diseases, but also find ways to offer personalized treatments based on a person’s specific genetic make-up.
 
 

[More to come ...]



 

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