Peripheral vascular disease in cigarette smokers and impaired hepatic metabolism of lipoprotein remnants.

The metabolism of very-low-density lipoproteins and chylomicrons includes the extrahepatic hydrolysis of their triglycerides by lipoprotein lipase. This results in cholesterol-rich "remnants" which are further metabolised by the liver. There is experimental evidence that in both patients with type-III hyperlipoproteinaemia and cigarette smokers hepatic-remnant metabolism may be depressed. In type-III hyperlipoproteinaemia the defect is inherited while in smokers it occurs in response to raised blood concentrations of carboxyhaemoglobin. The striking clinical similarity between type-III hyperlipoproteinaemic patients and smokers--namely, a high incidence of peripheral vascular disease--may be due to a common cause, the accumulation of cholesterol-rich remnants in the plasma.