Good Cholesterol Was About Function, Not Quantity — Confirmed in 61 Patients with Coronary Artery Disease (Institute of Science Tokyo)

Explanation

Many people have seen the value of HDL, called "good cholesterol," on a health checkup. It has been explained that the higher the value, the less likely one is to develop arteriosclerosis. However, in recent years, results have repeatedly shown that raising HDL levels with drugs does not reduce heart disease. The numbers and the actual disease did not match.

On August 18, 2026, a research group at the Institute of Science Tokyo announced that it had shown the reason for this discrepancy in the actual blood vessels of patients. The answer is that "HDL should be evaluated by function, not quantity."

The original job of HDL is to collect excess cholesterol accumulated on blood vessel walls and carry it to the liver. This collecting ability is called "cholesterol efflux capacity (CEC)." However, measuring CEC has been difficult until now. It required cultured cells and radioactive substances, and the effort and equipment involved meant it could not be measured in many patients.

The research group developed a measurement method called the ILG method (Immobilized Liposome-bound Gel bead method). It allows CEC to be measured without using cells or radioactive substances. The mechanism fixes artificial lipid membranes (liposomes) onto gel beads and observes how much cholesterol HDL can extract from them.

Using this method, the group examined 61 patients with coronary artery disease and simultaneously imaged the inside of the coronary arteries using optical coherence tomography (OCT). OCT is an examination that uses light to closely observe the walls of blood vessels, revealing the size and nature of plaques (raised areas that form on vessel walls).

As a result, patients with large, lipid-rich plaques had lower CEC. On the other hand, no difference was found in the HDL cholesterol value itself. This means that even at the same numerical value, there was HDL that was functioning and HDL that was not.

This is reportedly the first time that CEC, measured by a cell-free method, has been shown to be linked to actual coronary artery plaques in patients. It may be possible to detect the risk of arteriosclerosis at an earlier stage than with conventional blood lipid values.

It should be kept in mind that the study involved 61 patients. Because it is a study that individually matched blood measurements and vascular images for coronary artery disease patients, its nature differs from health-checkup surveys involving tens of thousands of people. The relationship that "people with low CEC have larger plaques" is not the same as saying that "measuring CEC can predict future heart disease." Confirming predictive power requires following a much larger number of people over a longer period.

Nevertheless, it is significant that something previously impossible to measure without cells and radioactive substances can now be measured without either. Only once it becomes measurable can the next stage—examining large numbers of people—proceed.

The paper was published in the journal Atherosclerosis.

Source: Institute of Science Tokyo, "Why a high concentration of the 'good cholesterol' particle HDL is not necessarily reassuring" (August 18, 2026)
https://www.isct.ac.jp/ja/news/dmwd9j5lb5lx