On 2017 Nov 18, Kenneth J Smith commented:
The authors agree, of course, that MS lesions predominantly occur around veins, and we make this point in our paper. A purpose of our paper is to provide a deeper understanding of how perivenous lesions can arise due to tissue hypoxia. We make the point that hypoxia in arterial watershed territories will exacerbate the venous influence on lesion genesis.
On 2017 Oct 22, Franz Schelling commented:
The fact that the MS lesion patterns observed in the brain do not reflect arterial border zones, the "last meadows" of arterial perfusion, but an unexplained kind of venous impacts has become more and more evident since 1911. In this year, Alexander Bruce for the first time noted the lesion arrangements along tributaries of the internal cerebral veins. And up to the latest MRI studies, the cerebral MS lesions' vascular relationships have consistently spoken not of central lesion arteries but of central lesion veins.
On 2017 Nov 18, Kenneth J Smith commented:
The authors agree that it is well established that the grey matter has a higher metabolic rate than the white matter, and this is in accord with the higher vascular density in the grey matter. This fact does not address whether oligodendrocytes are particularly susceptible to tissue hypoxia. There is widespread experience that oligodendrocytes are very vulnerable, although the underlying reasons remain unclear. The location of oligodendrocytes in the white matter accentuates their vulnerability, not only due to the relative paucity of the vasculature, but also because of the propensity of the white matter vasculature to contain relatively deoxygenated blood.
On 2017 Oct 22, Franz Schelling commented:
To come closer to the point: Why needs the cerebral grey matter fife to then as much arterial perfusion, oxygen and nutrients than the cerebral white matter? It is the presence of nerve cells as these are present in the grey matter alone. All the other tissue constituents occur in both white and grey matter.
The far higher density of blood vessels in the grey as against the white brain tissues testifies equally to the higher metabolic demands of the nerve cell containing - and not of the oligodendrocyte rich tissue.
On 2017 Nov 18, Kenneth J Smith commented:
The authors do not believe they have deepened any misconceptions. First, we make no claims that Dawson’s fingers are identical to arterial border zones. However, the fact that many MS lesions bear a relationship with arterial border zones has been clearly established, not least in the several detailed studies of thousands of lesions that we cite from other groups. Second, we do not claim that oligodendrocytes’ metabolic demands are generally as high as those of neurons. We do claim that oligodendrocytes are particularly vulnerable to hypoxia, and this is the experience of many investigators. We devote a section to this topic in our manuscript.
On 2017 Oct 17, Franz Schelling commented:
It is a pity this paper deepens two elementary misconceptions: (1) The assumption the MS-specific ventricle-based lesion-formations (Dawson's fingers) were identical with arterial border-zone lesions - as the latter occasionally touch the ventricular border. (2) The opinion, the oligodendrocytes' metabolic demands were generally as high as those of the neurons. Not only the given authors but also the public at large can only be recommended to study the pertinent evidence more carefully so as not to fall prey to easily reiterated mistaken assumptions regarding these pivotal points.
On 2017 Oct 17, Franz Schelling commented:
It is a pity this paper deepens two elementary misconceptions: (1) The assumption the MS-specific ventricle-based lesion-formations (Dawson's fingers) were identical with arterial border-zone lesions - as the latter occasionally touch the ventricular border. (2) The opinion, the oligodendrocytes' metabolic demands were generally as high as those of the neurons. Not only the given authors but also the public at large can only be recommended to study the pertinent evidence more carefully so as not to fall prey to easily reiterated mistaken assumptions regarding these pivotal points.
On 2017 Oct 22, Franz Schelling commented:
To come closer to the point: Why needs the cerebral grey matter fife to then as much arterial perfusion, oxygen and nutrients than the cerebral white matter? It is the presence of nerve cells as these are present in the grey matter alone. All the other tissue constituents occur in both white and grey matter.
The far higher density of blood vessels in the grey as against the white brain tissues testifies equally to the higher metabolic demands of the nerve cell containing - and not of the oligodendrocyte rich tissue.
On 2017 Oct 22, Franz Schelling commented:
The fact that the MS lesion patterns observed in the brain do not reflect arterial border zones, the "last meadows" of arterial perfusion, but an unexplained kind of venous impacts has become more and more evident since 1911. In this year, Alexander Bruce for the first time noted the lesion arrangements along tributaries of the internal cerebral veins. And up to the latest MRI studies, the cerebral MS lesions' vascular relationships have consistently spoken not of central lesion arteries but of central lesion veins.