It should be noted, however, that the associations between elevated LDL-C and blood pressure and increased CVD risk reflect causal relationships, whereas such a relation between low HDL-C levels and increased CVD is not undisputed (6, 7).
In conclusion, the epidemiological association between HDL and CVD is strong and is largely responsible for the formulation of the HDL hypothesis, but in itself does not prove a causal relationship.
Käänteisen kolesterolinkuljetuksen teoria on hyvin kyseenalainen:
Altogether, there is no evidence for a role of HDL in the net removal of cholesterol from the body (or vascular wall) and subsequent excretion into feces in mice, whereas evidence in humans is very scarce. To date, there are no assays to measure cholesterol efflux that have proven value in predicting cardiovascular events in humans. This reflects the inherent difficulty of finding a measure for the complex dynamics of cellular cholesterol exchange in atherosclerotic lesions.
The overall RCT hypothesis, especially with respect to the relationship between plasma HDL cholesterol and fecal cholesterol excretion, has been challenged by findings in both mice and humans.
Sama koskee muita vaikutuksia:
In conclusion, there is considerable evidence for a direct protective role of HDL in inflammatory, oxidative, apoptotic, and thrombotic processes but these studies are primarily performed in in vitro settings. With respect to protection from endothelial dysfunction, some evidence suggests that in vitro findings may apply to in vivo situations as well but studies are small. In each case, a direct link between ex vivo measurements (biomarkers) and cardiovascular risk is yet to be established. Because such evidence could strengthen the concept that HDL is an actor rather than a bystander in atherogenesis, an important challenge for the coming years will be the translation of HDL function assays from bench to bedside. These assays are particularly needed in view of the ongoing testing of novel HDL drugs in clinical trials where early indications of success or failure are absolutely vital.