The long quest for a missing mechanistic rationale accounting for the correlation between plasma
cholesterol levels and
cardiovascular disease (CVD) has been focused on various possible modifications of
low density lipoprotein (
LDL), turning this physiological
cholesterol carrier into a damaging agent able to trigger
atherogenesis and later the onset of the disease. In addition to the debated
oxidized LDL (
oxLDL), a modified
LDL with a misfolded
apoprotein B-100, called electronegative
LDL(-) for its negative charge due to an increased amount of
free fatty acids, is commonly present in plasma.
LDL(-) is generated by the action of secretory
calcium dependent
phospholipase A2.
LDL(-) primes
LDL aggregation and
amyloid formation according to mechanisms very similar to those observed in other misfolding diseases. The
LDL particle aggregates recall the structure and size of the subendothelial lipid droplets described in early
atherogenesis and elicit a powerful inflammatory response. The use of 17-β-estradiol (E2) confirmed that the suggested atherogenicity of
LDL (-) is mostly dependent on the misfolded character of its
apoprotein. E2 binding to the
apoprotein of native
LDL, through a specific and saturable receptor, inhibits misfolding phenomenon despite an unaffected production of
LDL (-) by
phospholipase A2, ultimately preventing
LDL aggregation. The
apoprotein misfolding in
LDL(-) emerges as a possible significant trigger mechanism of
atherogenesis. Potential implications for the development of novel therapeutic approaches might be hypothesized in perspective. The existing evidence is discussed and reported in this review.