Histochemical study on lipid metabolism in acute myocardial infarction.

As a part of the series of studies on lipid metabolism in ischemic myocardium, the present study was attempted to analyse 29 infarcted hearts with acute or scar lesions by a routine histopathology and lipid histochemistry. The time after the onset of attack till death ranged from one day to years. Sixteen were of the acute form, less than 2 month-old, and 13 were of the chronic scarred form. Within the first day, fat deposition appeared in the survived muscle cells around the infarcts reaching the peak from 2 days to one week, but necrotized cells never contained fat droplets. Macrophages in granulation tissue in periphery of the infarcts tended to have significant fat droplets usually in 10 days to one month. Fat disappeared from the survived muscle cells and also from the scar later than 2 months. The survived cells around the infarcts might be degenerated with fat, probably triglyceride, which accumulated by a relative ischemia not severe enough to produce coagulation necrosis, and they bear some relationship with extension or limitation of size of infarcts.