A Power Program for Student Review
Course Coverage 2016
- Jan Fit To Last
- Feb Urbanized Eating
- Mar Mind & Memory
- April Special Senses
- May Metabolic Syndromes
- June Sugar Diabetes
- July Diabetes Complications
- Aug Aging
- Sept Atheroma
- Oct Longevity
- Nov Cancer
- Dec Predicaments
Last month’s perspective on longevity was: Atheroma…and a summary of its content is reviewed in this Countdown.
Let’s begin with cholesterol, an essential building block in all the cells of a body. A cell wall stabilizer, it is essential to life. Cholesterol is present in the food we eat, and is also made in the liver. It circulates in the blood for tissue used in cell repair and construction. In excess, however, whether from diet or liver overproduction it accumulates in the arteries as atheroma. There it can cause much modern mischief like heart attacks and strokes.
Imagine for a moment that you’re a red blood cell…a tiny package of oxygen-carrying hemoglobin inside a fragile shell. You’re pummeled, pushed, choked, channeled, squeezed and squirted…endlessly out and back over miles of blood vessels in a recycling system called the circulation. You are gathered up in the heart for less than a second before squirting through a narrowing maze of arteries, and eventually into ones so fine that you can only get through single file. That’s where you give up your oxygen, and take on carbon dioxide. Back and forth you go in a brief existence that survives in the average circulation only a brief 4 months.
You live this life within the body’s blood vessels: its arteries, veins and capillaries, all lined by a delicate membrane, as tough and translucent as food wrap. Called the intima, it has a glass-smooth surface formed by flat pancake cells, like a flagstone walk, whose job is to contain the blood and keep it flowing, while allowing molecules like oxygen, nutrients and carbon dioxide to enter or exit the tissues. This enormous surface area of glistening intima must protect you, a red cell, from damage while performing your neighborhood delivery & pick-up chores.
The intima lining in the arteries also overlies two distinct artery wall layers. There is an inner muscular layer that gives each artery strength and tone, and outside the muscular layer a fibrous tissue coat that anchors blood vessels in place throughout the body. The intima, is in constant contact with the blood and its contents including a modern villain, now a household name. Cholesterol can penetrate the edges of intima pancakes between its cells, and get stuck between intima and muscle layer in deposits that are called atheromas.
Cholesterol circulates in the blood in protein wrappers, like a rolled taco in 3 different bread wrappers. It is called lipoprotein cholesterol…and 3 types were first separated i the lab by centrifuge, hence their names: HDL, LDL and VLDL. Very Lo Density Lipoprotein is the least friendly. It slips so easily through intima cell edges into artery walls. At first doing so in a two way process, coming and going, but eventually it stays as a deposit which arteries hate, like your skin hates a splinter.
An artery regards any cholesterol deposit as you would a finger splinter. It treats the deposit like a foreign body, calling for immune pus cells to come and digest it. But cholesterol is indigestible. Once gobbled up by pus cells, it sits comfortably inside, eventually choking them and becoming a resident foreign body. The frustrated artery next tries isolation and weaves a web of fiber around the deposit to create the visible atheroma.
Unless defensive dietary steps are taken, artery cholesterol deposits persist and grow. They lump up into the artery’s tunnel and slow its flow of blood. As they age, over months and years, their fiber wrap stiffens and cracks. This exposes raw edges to the streaming blood, and raw edges attract circulating cells called thrombocytes. Their job is to form clots that can plug up an artery.
Circulating thrombocytes evolved in our antiquity to seal holes in arteries against blood loss. They were a defense against bleeding to death from injury. But the raw edges of a cracked atheroma pose no threat of blood loss, so their ancient function is inappropriate in this situation, creating a blocking clot or thrombus…a modern medical emergency that’s years in the making.
A thrombus in a coronary artery causes the heart attack. Heart muscle downstream loses its blood supply and may die, ending a life. A thrombus in a cerebral artery threatens brain parts, say the motor function of an arm and leg, causing a stroke. People take aspirin these days to prevent heart attacks and strokes by preventing their thrombocytes from collecting on the recurring fresh cracks over the atheromas that are scattered under the linings of their arteries.
A blood clot in the leg causes pain below the knee…pulses at the foot are absent or diminished…toes are whitened and can darken from gangrene. In the dairy country of Denmark (think: whole milk, butter, ice cream and cheese) most men over 40 begin lifetime dosing with statin drugs to lower their blood cholesterols. It’s a cost saving move for their National Health Plan, and a market preserver for the Dairy Industry.BLAST OFF