The retina and the optic nerve are the only extensions of the CNS that can be observed non-invasive. The retina in MS is known to degenerate and is unknown how, as there is no myelin on the retina and current MS models do not explain this problem.
Two new articles have found that retinal degeneration is linked to blood flow problems in the eye.
I would challenge any supporter of the autoimmune model to explain these facts with T-cells.
Impaired retinal microcirculation in multiple sclerosis.
https://www.ncbi.nlm.nih.gov/pubmed/26903007
CONCLUSION: The impaired retinal microcirculation in RRMS patients indicates microvascular dysfunction in MS.
Detection of retinal blood vessel changes in multiple sclerosis with optical coherence tomography.
https://www.ncbi.nlm.nih.gov/pubmed/27375947
MS eyes had a lower total BVD (Blood vessel diameter) and BVN (blood vessel number) than control eyes. The effect was more pronounced with increased MS disability
vascular problems also found in the retina
Re: vascular problems also found in the retina
https://www.ncbi.nlm.nih.gov/pubmed/19384781
Here's how they tried to explain it with the inflammation/autoimmune hypothesis in this 2009 research:
Here's how they tried to explain it with the inflammation/autoimmune hypothesis in this 2009 research:
They have to include the part about negative history of optic neuritis still having subclinical swelling because the findings don't correlate with optic neuritis, which weakens this as an explanation.CONCLUSION:
Narrower arterioles and wider venules might be a consequence of subclinical swelling of optic nerve axons in eyes with negative history of ON in MS patients.
Re: vascular problems also found in the retina
Here's research supporting the explanation I would go with, which is slowed drainage leading to perfusion impairment and reperfusion injury in the eyes:
research is in rats though
reperfusion injury impacts leukocytes, not leukocytes impacting the capillaries initially
https://www.ncbi.nlm.nih.gov/pubmed/10520216Curr Eye Res. 1999 Nov;19(5):403-10.
Quantitative analysis of leukocyte dynamics in retinal microcirculation of rats with short-term ischemia-reperfusion injury.
Lu N1, Shimura M, Kinukawa Y, Yoshida M, Tamai M
Abstract
PURPOSE:
To characterize the time course of complete recovery of leukocyte velocities in the retinal microcirculation of rats from short-term (5-minute) retinal ischemia.
METHODS:
After 5 minutes of retinal ischemia produced by clamping the optic nerve, resulting in the occlusion of both central retinal artery and the central retinal vein, we used acridine orange (AO) and a scanning laser ophthalmoscope (SLO) to observe the velocities of leukocytes in precapillary arteriole ( v(a)), capillary (v(c)) and postcapillary venule (v(v)). Measurements were taken at reperfusion time points of 5, 10, 15, 20, 30, 40, 50, 60 and 80 minutes for the ischemic eyes and at 12, 22, 42 and 62 minutes for the control eyes, respectively.
RESULTS:
Each control velocity was arteriole 25.1 +/- 4.3 mm/ s; venule 16.9 +/- 3.2 mm/s; and capillary 1.54 +/- 0.31 mm/s, respectively. The leukocyte velocities after 5 minutes of ischemia in arteriole and venule recovered completely within 80 minutes of reperfusion; however, the recovery patterns were different. The recovery pattern showed a biphasic increase in arterioles and a monophasic increase in venules. The velocity in capillaries half recovered rapidly, within 5 minutes of reperfusion, but the subsequent recovery was slower and was not complete even at 80 minutes of reperfusion.
CONCLUSIONS:
In this study, leukocyte velocities in arterioles, venules and capillaries exhibited different recovery patterns following retinal ischemia and subsequent reperfusion. Capillaries, at least within 80 minutes of reperfusion, may have difficulty recovering completely from even short-term (5-minute) ischemia.
research is in rats though
reperfusion injury impacts leukocytes, not leukocytes impacting the capillaries initially
Re: vascular problems also found in the retina
Thanks Cece. I didn't know that. I suppose it makes sense somehow.Cece wrote: Here's how they tried to explain it with the inflammation/autoimmune hypothesis in this 2009 research:
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