Fibrinogen is always present in the blood.The normal range is 200 - 400 milligrams per deciliter (mg/dL).
Fibrinogen is a protein which is made in our livers. It's the sigaling protein for fibrin, which allows our blood to clot. When people develop venous ulcers on their legs, due to chronic venous insufficiency, it's fibrinogen that leaks from the veins and creates a build up of fibrin, depleting the tissue of oxygen and allowing those hallmark ulcers to form. This is called a "fibrin cuff." It's fibrinogen which initiates the coagulation cascade and causes our blood to thicken, as a response to low oxygen levels.
Dr. Zamboni was the first to suggest that MS lesions looked a lot like venous ulcers because of the fibrin cuffs found in both sites of injury. And researchers have noted that fibin deposition comes FIRST, before demylination.
Compromised vasculature in the nervous tissue is a pathogenic manifestation apparent in traumatic injuries, such as spinal cord, optic nerve, and sciatic nerve injury, as well as in central nervous system (CNS) diseases with autoimmune characteristics, such as multiple sclerosis (MS) (7). Blood-brain barrier (BBB) disruption precedes clinical symptoms in MS patients (8), and fibrin is deposited in the lesions (9, 10), apparently before cerebral tissue injury and demyelination (11). Fibrin deposition also coincides with areas of demyelination (12), as well as with areas of axonal damage.http://www.pnas.org/content/101/17/6698.full
This finding, in accord with the earlier literature , suggests the presence of a procoagulant state in MS, and elements of the coagulation system such as fibrin and tissue factor (TF) are found in MS lesionshttp://www.jneuroinflammation.com/content/5/1/27
In particular, a proinflammatory role for fibrinogen has been reported in vascular wall disease, stroke, spinal cord injury, brain trauma, multiple sclerosis, Alzheimer's disease, rheumatoid arthritis, bacterial infection, colitis, lung and kidney fibrosis, Duchenne muscular dystrophy, and several types of cancer.http://www.ncbi.nlm.nih.gov/pubmed/22037947
A fibrous protein called fibrinogen, found in circulating blood and important in blood clotting, can promote multiple sclerosis when it leaks from the blood into the brain, triggering inflammation that leads to MS-related nerve damage. Researchers at the University of California, San Diego (UCSD) School of Medicine have identified a fibrin-derived peptide that inhibits this specific inflammation process in mouse models of MS, reducing MS symptoms.http://www.sciencedaily.com/releases/20 ... 105436.htm
The most important take away from all of this is that according to this brand new research, the first thing that happens after the BBB is breached is the crossing over of fibrinogen, which is toxic to neurons. Neuronal death precedes demyelination and inflammation.
And neuronal death is found in progressive MS (as measured by gray matter loss)---even though there is no inflammation present.