THBS1 and atherosclerosis: Thus, while the KK background alone may result in a pre-diabetic phenotype manifesting sex-specific differences in lesion burden and proatherogenic status, an ectopic expression of the agouti gene on the KK background (KKAy+/–) is more likely to augment TSP-1 expression accelerating atherosclerosis, and this effect occurs independent of differences in sex.