The greatest challenge to this traditional explanation has been presented by Professor Vladimir Subbotin (9-11). The challenge hinges on two facts that are irrefutably true, and either of which by itself irretrievably undermines any proposed theory of how LDL-cholesterol from the blood crosses the lining of the arteries — i.e., the endothelium — and collects in the subendothelial space in the tunica intima, initiating the process of atherosclerosis as depicted in Figures 1 and 2.

The first point made by Subbotin as early as 2012 (9) and repeatedly since (10, 11) is that the tunica intima, including the so-called subendothelial space, is not an empty space without cells and filled only with structural proteins. This is the way it is depicted in Figures 1 and 2. Subbotin argues the only reason why the diagram is drawn that way is because Keys’ lipid hypothesis demands it to be so. Without that space, the lipid hypothesis in its original form is logically disproven.

This is the only model that would explain how LDL-cholesterol particles might be able to “slip” — Subbotin uses the word “crawl” (11) — easily through a damaged endothelial lining to enter the acellular subendothelial space, where they are engulfed by invading macrophages, thus initiating the process of progressive atherosclerosis. But if this (hypothetical) acellular subendocardial space is not acellular but instead comprises layer upon layer of mature cells, how will the LDL-particles find their way between those cells? And how, among all those layers of cells, will the macrophages be able to locate the LDL invaders?

Subbotin cites the utterly fundamental and completely ignored work of Yutaka Nakashima et al. (12-14), which reveals two essential findings that destroy Keys’ lipid hypothesis. Interestingly, Nakashima and colleagues avoid any reference to the possibility that their work disproves Keys. Only Subbotin has had the courage to advance this heretical possibility.

The first finding is that histological examination of adult coronary arteries shows the tunica intima does not comprise a single layer of endothelial cells sitting atop an acellular empty space that exists, just waiting to be filled by LDL-cholesterol and engulfing macrophages. This is shown in Figure 3.

Figure 3: The study of Nakashima et al. (12) shows the tunica intima is not an empty acellular space as depicted in Figures 1 and 2. Instead, the tunica intima comprises multiple layers of cells (panels a and b) and is in fact thicker than the tunica media. Using a special stain to identify smooth muscle cells, panel c shows the cells in the tunica intima, below the endothelial layer, are indeed smooth muscle cells. Panel d stains for the presence of macrophages, which are identified with an arrow head. This evidence shows the diagrams depicted in Figures 1 and 2 are fundamentally incorrect in depicting the tunica intima as an acellular space potentially full of macrophages. Reproduced from Figure 3 in reference 10.

In contrast, the tunica intima comprises multiple layers of smooth muscle cells — up to 50 such layers — and without any macrophages.

Free article

doi: 10.1016/j.drudis.2016.05.017. Epub 2016 Jun 2.Review. 2016 Oct;21(10):1578-1595.Drug Discov Today

Excessive intimal hyperplasia in human coronary arteries before intimal lipid depositions is the initiation of coronary atherosclerosis and constitutes a therapeutic target
Vladimir M Subbotin 1
DOI: 10.1016/j.drudis.2016.05.017

Abstract

The consensus hypothesis on coronary atherosclerosis suggests high LDL-C levels as the major cause and pursues it as the therapeutic target, explicitly assuming: (i) tunica intima of human coronaries consists of only one cell layer - endothelium, situated on a thin layer of scarcely cellular matrix; and (ii) subendothelial lipoprotein retention initiates the disease. Facts showed: (i) normal tunica intima invariably consists of multiple cellular layers; and (ii) initial lipid depositions occurred in the deepest layers of tunica intima. This review suggests that coronary atherosclerosis starts with pathological intimal expansion, resulting in intimal hypoxia and neovascularization from adventitial vasa vasorum, facilitating lipoprotein extraction by previously avascular deep intimal tissues. Until the hypothesis incorporates real knowledge, our efforts will probably be off-target