Table 2.

Characteristics of animal studies related to atherosclerosis included in the review.

Study	Disease/ Condition	Study Type/ SQ Source	Sample/ Population	Methodology	Results (SQ and CVD only)	Comments/Outcomes
Study 1 Kritchevsky et al. (1954) [55]	Atherosclerosis	Animal study   Purchased from Distillation Products Inc, Rochester, NY, USA.	Male rabbits (1.5 to 2 kg)   Divided into five groups	Rabbits were randomly divided into five groups as follows: group I: normal diet (N), group II: N + SQ, group III: N + SQ (14 weeks), group IV: N + cholesterol, and group V: N + SQ + cholesterol.   The treatments were prepared at 3% of the total diet and were mixed with corn oil. All groups were maintained on the diets for seven weeks, except for group III (14 weeks duration).   After the treatment, the livers were weighed and assayed for total non-saponifiable material, cholesterol, and SQ. The aortas were visually examined for atherosclerotic lesions and were graded on a 0 to 4 plus scale (in the order of increasing severity). Ultra-centrifugal examination of the serum for β-lipoproteins was also performed.	a) Atheromatous lesions: SQ-alone-supplemented groups (II and III) did not develop lesion and corresponded to those seen in group I. The cholesterol- alone (group IV) and SQ + cholesterol feeding (group V) showed the highest degrees of average atheroma.   b) Liver weight and total non-saponifiable material: The liver weight of seven-week squalene supplementation (group II) increased markedly when compared to the normal group (group I). There was an increase in total non-saponifiable material in all groups (II–V) compared to the normal group, with a much greater increase in groups IV and V.   c) Serum β-lipoproteins: The animals on the seven-week squalene diet showed no increase in their serum lipoproteins. As squalene feeding continued, there was an increase in the serum levels.	Supplementation of SQ may be regarded as a source of endogenous cholesterol and did not cause atherosclerosis.   Exogenous cholesterol played a more important role in the development of atherosclerosis than endogenous cholesterol.   SQ might increase liver weight and total non-saponifiable material; however, no development of atheroma was observed.
Study 2 Guill´en et al. 2008 [56]	Atherosclerosis	Animal study   Source of SQ was not disclosed.	Homozygous ApoE knockout mice (aged 2 months)   Divided according to sex (17 males, 15 females)	Both groups (male and female) were fed on a standard chow diet and were assigned into two groups with different beverages: i) SQ group, 1% (v/v) glycerol solution supplemented in squalene to provide a dose of 1 g/kg/day and ii) control group, glycerol solution (vehicle). Duration of treatment: Ten weeks   At the end of the treatment, the mice were sacrificed for blood collection and heart excision. Measurement involved a) plasma lipid and lipoprotein, b) liver parameters, c) area of atherosclerotic lesion, d) antioxidant defenses (paraoxonase activity and isoprostane levels), and e) hepatic apolipoprotein.	One% SQ supplemented in beverage significantly decreased plasma cholesterol, triglycerides, and Apoa1 in females (p < 0.05), while there was no change in males.   The liver weight was significantly decreased in males consuming SQ (p < 0.05), while this effect was not evident in females. Male mice receiving SQ showed a significant decrease in fat in the liver (p < 0.05).   Males receiving SQ showed a significant decrease in the lesion (p < 0.01), while female mice showed no change in their lesion area.   In males, there was a high statistically significant direct correlation (rs = 0.81; p < 0.000) between hepatic weight and plasma triglycerides. A statistically significant direct association (rs = 0.64; p < 0.02) was also observed between the lesion area and hepatic fat accumulation.   SQ intake significantly decreased plasma levels of 8-isoprostaglandin F2 in both sexes (p < 0.05).   No significant change in hepatic Apoa1 mRNA levels in both sexes   Male mice receiving SQ showed significantly increased Apoa5 expression (p < 0.01).	The administration of SQ modulates lesion development in a sex-specific manner.   The accumulation of hepatic fat by the liver is highly correlated with lesion progression in males.   SQ administration could be used as a safe alternative to alleviate atherosclerosis and hepatic steatosis, particularly in males.