Monday, September 27, 2010

6. Fat Cells, Macrophages and Atherosclerosis

While diligently converting glucose to stored fats, the fat cells are awash in glucose, which damages their apoE through glycation [Li1997]. Once their apoE is damaged, they can no longer transport cholesterol to the membrane. Excess cholesterol accumulates inside the fat cells and eventually destroys their ability to synthesize proteins. Concurrently, their cell membrane becomes depleted in cholesterol, because they can no longer deliver it to the membrane [Seneff2010]. A fat cell that has deteriorated to this degree has no choice but to die: it sends out distress signals that call in macrophages. The macrophages essentially consume the dysfunctional fat cell, wrapping their own membrane around the fat cell's membrane that is now barely able to hold its contents inside [Cinti2005].

Macrophages are also principle players in the fatty streaks that appear along the sides of major arteries leading to the heart, and are associated with plaque build-up and heart disease. In a fascinating set of experiments, Ma et al. [Ma2008] have shown that the sulfate ion attached to oxidized forms of cholesterol is highly protective against fatty streaks and atherosclerosis. In a set of in-vitro experiments, they demonstrated diametrically opposite reactions from macrophages to 25-hydroxyl cholesterol (25-HC) versus its sulfoconjugate 25-hydroxyl cholesterol sulfate (25-HC3S). Whereas 25-HC present in the medium causes the macrophages to synthesize and store cholesterol and fatty acids, 25-HC3S has the exact opposite effect: it promotes the release of cholesterol to the medium and causes fat stores to shrink. Furthermore, while 25-HC added to the medium led to apoptosis and cell death, 25-HC3S did not. I suggest that the sulfate radical is essential for the process that feeds cholesterol and oxygen to the heart muscle.

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