High Cholesterol Link To Osteoarthritis

High cholesterol has been linked to mitochondrial stress in cartilage cells - causing cell death and osteoarthritis development

Despite the essential nature of cholesterol itself, hypercholesterolemia, (excess cholesterol in the blood) causes a range of health problems and is strongly associated with increased risk of coronary artery disease. While we already know many of the risks of raised cholesterol, researchers have now linked increased blood cholesterol concentrations to osteoarthritis onset as well. 

Cholesterol and mitochondrial stress

Using a genetic mouse model of hypercholesterolemia caused by the presence of two particular alleles of ApoE (-/- ), and a rat model of hypercholesterolemia induced by dietary intervention, researchers studied the effect of cholesterol levels on bone health. They also mimicked knee injury in both groups through surgery and observed the effect of cholesterol on recovery. Interestingly, groups that had undergone injury and demonstrated high cholesterol in particular displayed more severe osteoarthritis development - whether induced by diet or genetics. 

"Just when we thought all the angles on osteoarthritis had been uncovered, a new lead like this comes along. The focus of hypercholesterolemia, whether familial or sporadic, has, of course, always been on arterial disease, but here we have a fascinating new discovery"

When the scientists looked closer, they found that high cholesterol was associated with a loss of proteoglycans, collagen and aggrecan, formation of bone spurs, changes to subchondral bone architecture, and cartilage degradation. Raised levels were somehow driving overproduction of reactive oxygen species in the mitochondria of cartilage cells, which lead to progressive changes and dysfunction as well as cell death.

A possible therapeutic option  

When the team subjected both rat and mouse groups to both cholesterol lowering drugs such as atorvastatin or mitochondrial targeted antioxidants, the rate of osteoarthritis progression was markedly reduced in all at risk groups. Although there are other processes driving osteoarthritis, the study hints that mitochondrial targeted antioxidants and cholesterol lowering interventions may slow osteoarthritis progression in certain cases at least.

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