High Density Lipoprotein Level is Negatively Associated With the Increase of Oxidized Low Density Lipoprotein Lipids After a Fatty Meal

Lipid Oxidation Products and the Risk of Cardiovascular Diseases: Role of Lipoprotein Transport

Cholesterol has for decades ruled the history of atherosclerotic cardiovascular diseases (CVDs), and the present view of the etiology of the disease is based on the transport of cholesterol by plasma lipoproteins. The new knowledge of the lipoprotein-specific transport of lipid oxidation products (LOPs) has introduced another direction to the research of CVD, revealing strong associations between lipoprotein transport functions, atherogenic LOP, and CVD. The aim of this review is to present the evidence of the lipoprotein-specific transport of LOP and to evaluate the potential consequences of the proposed role of the LOP transport as a risk factor. The associations of cholesterol and lipoprotein LOP with the known risk factors of CVD are mostly parallel, and because of the common transport and cellular intake mechanisms it is difficult to ascertain the independent effects of either cholesterol or LOP. While cholesterol is known to have important physiological functions, LOPs are merely regarded as metabolic residues and able to initiate and boost atherogenic processes. It is therefore likely that with the increased knowledge of the lipoprotein-specific transport of LOP, the role of cholesterol as a risk factor of CVD will be challenged.

Beneficial effects of cocoa, coffee, green tea, and garcinia complex supplement on diet induced obesity in rats

Background

Cocoa, coffee, green tea and garcinia contain large amounts of polyphenols. Polyphenols are well-known phytochemicals and found in plants, and have modulated physiological and molecular pathways that are involved in energy metabolism, adiposity, and obesity.

Methods

To evaluate the obesity-lowering effect of a combined extract (comprising cocoa, coffee, green tea and garcinia; CCGG) in high-energy diet (HED)-induced obese rats. Male Sprague Dawley rats (8 weeks old) were randomly divided into four groups (n = 12 per group): normal diet with vehicle treatment (Control), and HED to receive vehicle or CCGG by oral gavage at 129, 258, or 517 mg/kg/day for 4 weeks, designated the HED, 0.5X, 1X and 1X groups, respectively.

Results

HED induced macrovesicular fat in the liver and the formation of adipose tissues, and significantly increased the levels of serum free fatty acids (FFA), triacylglycerol (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and LDL-C/HDL-C, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and ketone bodies in serum, and hepatic TG and TC levels, and decreased the levels of high density lipoprotein cholesterol (HDL-C) in serum and lipase activity in fat tissues. Treatment with CCGG could significantly decrease the levels of FFA, TG, TC, LDL-C, and LDL-C/HDL-C, AST, ALT, and ketone bodies in serum, and hepatic TG and TC contents, and increase the levels of HDL-C in serum and lipase activity in fat tissues compared to the HED group. Liver histopathology also showed that CCGG could significantly reduce the incidence of liver lesions.

Conclusion

These results suggested that CCGG stimulated lipid metabolism in HED-induced obese rats, which is attributable to fat mobilization from adipose tissue.

Oxidized HDL and LDL in adolescents with type 2 diabetes compared to normal weight and obese peers

OBJECTIVE

Obesity and type 2 diabetes mellitus (T2DM) are associated with oxidative stress. Oxidative damage of high-density lipoprotein (oxHDL) leads to a dysfunctional molecule, potentially a mediator and/or marker of cardiometabolic disease. We tested the hypothesis that circulating concentration of oxHDL is higher in obese (Ob) or T2DM adolescents compared to normal-weight (NW) peers.

METHODS

In 37 NW, 38 Ob, and 42 T2DM adolescents, ages 11-18 y, fasting concentrations of HDL and LDL cholesterol, oxHDL, oxidized low-density lipoprotein (oxLDL), and myeloperoxidase (MPO) were measured.

RESULTS

Compared to the NW group, oxHDL in the Ob group was not different, but was 65% higher (p < 0.01) in the T2DM group. Within the T2DM group oxHDL was higher in boys than in girls, but this sex difference was not evident in NW or Ob groups. OxLDL was 23% higher in Ob (p = 0.02), and 56% higher in T2DM (p < 0.01) versus NW and did not differ between boys and girls. MPO was not different between NW and Ob but was 88% (p < 0.02) higher in T2DM compared to NW. Contrary to our hypothesis MPO and insulin resistance (HOMA-IR) were not correlated with oxHDL. OxHDL was positively associated with oxLDL and lean body mass while oxLDL was positively associated with apolipoprotein B, triglycerides, HOMA-IR and trunk fat.

CONCLUSIONS

The higher concentrations of oxHDL and oxLDL, along with higher MPO in children with T2DM reflect higher oxidative stress compared with obesity alone and potentially increased cardiovascular disease risk in youth with T2DM.