The Natural History of Atherosclerosis

The atherosclerotic process is associated with the aging process. Having been documented in the autopsies of ancient mummies, atherosclerosis appears to be universal in humans throughout the history of mankind. This natural history can be documented in every human.

The natural history of atherosclerosis begins at birth. The arteries are patent and clean at birth. Atherosclerosis begins in childhood ( by the age of 10) as deposits of cholesterol and its esters, referred to as fatty streaks, in the intima of large muscular arteries.


In some people and at certain arterial sites, more lipid accumulates and is covered by a fibromuscular cap to form a fibrous plaque. Further changes in fibrous plaques render them vulnerable to rupture, an event that precipitates occlusive thrombosis and clinically manifest disease (sudden cardiac death, myocardial infarction, stroke, or peripheral arterial disease).

In adults, the fibrous plaque invades a large part of the artery, damaging the artery to the extent of precipitating a clinical event. This stage of the disease is called "Clinical Lesions".  Elevated non-HDL-cholesterol concentrations, low HDL-cholesterol concentrations, hypertension, smoking, diabetes, and obesity are associated with advanced atherosclerotic lesions and increased risk of clinically manifest atherosclerotic disease.


The figure below shows the natural history of atherosclerosis against the ageing process:

The development of the fatty streak in childhood is depicted as a reversible process. In adolescence, some fatty streaks accumulate more lipid and begin to develop a fibromuscular cap, forming the lesion termed a fibrous plaque. In subsequent years, fibrous plaques enlarge and undergo calcification, hemorrhage, ulceration or rupture, and thrombosis. Thrombotic occlusion precipitates clinical disease, depending on which artery is affected.

Reference:
http://www.indiana.edu/~k562/athero.html

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Atherosclerosis in Ancient Egypt

Atherosclerosis and vascular calcification are usually regarded as circulatory phenotypes associated with advanced modern lifestyles, it is however evident in the remains of many ancient Egyptians. 

The mummification process was usually done for the more affluent members of society, and a rich legacy of archaeological and literary evidence, as well as the pathology preserved in both skeletal and mummified remains, has enabled disease studies to be undertaken. 

Marc Ruffer described arterial lesions in hundreds of Egyptian mummies in 1911 and Graham Shattock noted atheromatous deposits in the aorta of King Menephtah in 1909; these findings were later confirmed by John Harris and Edward Wente's radiological survey in 1980, which additionally reported vascular calcification (occurs frequently in atherosclerotic lesions) in the mummies of Ramesses II, Ramesses III, Sethos I, Ramesses V, and Ramesses VI.

Egyptologist Gomaa Abdel-maksoud prepares a mummy for a CT scan. The researchers were looking for evidence of arterial disease in the mummies. This mummy, Hatiay, who lived between 1550 and 1295 BC, had extensive vascular disease.

In 2009, computed tomography (CT) was used to assess atherosclerosis in a selection of 22 mummies of Egyptians with high social status. In 16 of these where the hearts or arteries could be identified, nine mummies showed evidence of vascular calcification. However, although arteriosclerosis has been clearly identified in mummies, it seems to have been fairly uncommon in ancient Egypt. This perhaps reflects the life expectancy at the time of between 40 and 50 years, even among the more affluent members of society, but may also result from differences in intakes of foodstuffs between most Egyptians and the affluent elite.

Computed Tomographic Examples of Atherosclerosis in Ancient Egyptian Mummies and a Contemporary Human

The palaeopathological evidence can now be examined in conjunction with ancient texts to provide further insight into the occurrence of the disease among the ancient Egyptian elite. Interpretation of the hieroglyphs indicates that the diet of the priests and their families consisted mainly of beef, wildfowl, bread, fruit, vegetables, cake, wine, and beer. Many of these food items would obviously have contributed to an intake of saturated fat. Moreover, Egyptian priests consumed little fish, and while oily fish is a major source of omega 3 fatty acids, which are also advocated in cardiovascular disease prevention, it is unlikely that the intake would have achieved anything like that required. 

It is important to point out that there was a marked difference between the mainly vegetarian diet most Egyptians ate and that of royalty and priests and their family members whose daily intake would have included these high levels of saturated fat. Mummification was practised by the elite groups in society, ensuring that their remains have survived to provide clear indications of atherosclerosis; by contrast, there is a lack of evidence that the condition existed among the less well-preserved remains of the lower classes. Since most mummies available for study will inevitably belong to the wealthier members of Egyptian society, most scientific data relate to the health of these people.

Sources:

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)60294-2/fulltext# 

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