Vascular Endothelial Growth Factor (VEGF)

What is Vascular Endothelial Growth Factor (VEGF)

Short Explanation

Vascular Endothelial Growth Factor (VEGF) is a signal protein produced by cells that stimulates the growth of new blood vessels in response to low levels of oxygen. It also produces a profound increase in vascular permeability and edema. (Permeability describes the blood vessel walls ability to allow small molecules such as water, nutrients or even whole cells such as white blood cells to go in and out of the vessel.)

Too much VEGF or too little VEGF can create problems. Too much VEGF can lead to excess blood vessel growth and excess permeability of capillaries. Too little can lead to a lack of oxygen in the tissues and symptoms of Chronic Inflammatory Respons Syndrome (CIRS). Initially in CIRS it will be high but it becomes low over time.

Detailed Explanation

Vascular Endothelial Growth Factor (VEGF) is a sub-family of the platelet-derived growth factor family of cystine-knot growth factors. It is a signal protein produced as a response to capillary hypoperfusion and Hypoxia Inducible Factor (HIF). VEGF has been shown to be an endothelium-dependent vasodilator, exerting its effect through Nitric oxide and prostacyclin. Though there are four endogenous isoforms of VEGF. VEGF-A is the one most often discussed when someone mentions VEGF. VEGF induces vascular permeability, cell migration and protease production by endothelial cells, all of which are critical components of the angiogenic process, the main function attributed to VEGF.

Low oxygen levels stimulate angiogenesis (Angiogenesis is the term used for the formation of new blood vessels from pre-existing ones). Among the many angiogenic factors, VEGF is one of the most critical and specific factors that stimulate both physiological and pathological angiogenesis.VEGF's function is to create new blood vessels during embryonic development, after injury for wound healing, in muscle following exercise and new vessels to bypass blocked vessels. When blood circulation is inadequate, VEGF will usually increase to meet the demand. The increased VEGF brings new blood vessels into the area and there is greater delivery of oxygen to the area.

In addition to its ability to induce vessel growth, a growing body of evidence has shown that VEGF is a survival factor that can enhance cardiomyocytes and neuronal cell survival and reduce infarct size in the brain and heart. [6]

Too much VEGF can lead to increased angiogenesis and create rampant growth of blood vessels.VEGF is used by some tumors to grow and metastasize. Increased VEGF is also associated with excess microvascular hyperpermability during inflammation.

Too little VEGF leads to decreased angiogenesis and lack of oxygen to the tissues. This has been associated with heart and brain ischemia (lack of oxygen), neurodegeneration. In the brain, VEGF stimulates the growth of new blood vessels and works in other ways to keep brain cells healthy. VEGF is currently being studied to treat the debilitating and fatal disease of the central nervous system called spinocerebellar ataxia type 1 (SCA1). Low VEGF also leads to delayed wound healing, high blood pressure and many symptoms seen in CIRS.

In a healthy individual there is a balance between switching angiogenesis on and off. This balance can be reflected in certain lab markers such as VEGF. We want VEGF to stay in a normal level that is seen in healthy individuals.

A VEGF Signaling Pathway can be viewed here.

High VEGF Issues

Cancer

Solid cancers get to a certain size and quit growing without more VEGF. They need more VEGF to create more blood vessels to bring enough oxygen and nutrients into them as they grow. Cancers that make VEGF are able to grow bigger and to metastasize (travel to other places). VEGF inhibitors are used in the treatment of some cancers.

Wet Macular Degeneration: Too much VEGF can cause over growth of blood vessels in the retina causing wet macular degeneration. Drugs such as Ranibizumab are used to inhibit VEGF in the retina of the eye.

Low VEGF in CIRS (Biotoxin Illness)

Dr. Ritchie Shoemaker found in his research that his CIRS patients often had low VEGF leading to levels less than 31. This was induced by high cytokine levels. He found they needed to keep their VEGF in the range of 31-86.

People with biotoxin illness such as those who have CIRS due to water-damaged building, will generally have low VEGF if they are extremely sick. Initially, the VEGF will rise due to tissue hypoperfusion. It is activated by hypoxia inducible factor (HIF). TGF beta-1 will also be induced by HIF and as it rises,TGF beta-1 will lower the VEGF level. Folks with CIRS due to water-damaged building have high TGF beta-1 generally.

Research has shown that the mycotoxin called fumagillin from Aspergillus fumigatus inhibits multiple key angiogenic mediators. VEGF is one of them. This leads to tissue hypoxia which can be reversed by VEGF introduction. [1] Researchers have created a fumagillin analog named Lodamin which is one of the most potent and broad-spectrum antiangiogenesis inhibitors. It's action on VEGF (inhibits VEGF induced angiogenesis by 41%) and basic fibroblast growth factor (inhibits VEGF induced angiogenesis by 31%). [2]This shows just how potent a mycotoxin or mycotoxin analog can be in inhibiting angiogenesis.

What is happening in CIRS when there is low VEGF

Basically, you end up with decreased delivery of nutrients and oxygen via the capillaries.

Three is low capillary hypoperfusion so you have a reduced delivery of O2 which leads to a reduced mitochondrial function and a rise of lactate.

These people can not exercise. They will crash due to the lack of oxygen to the capillary beds. It appears they are not efficiently burning glucose. They turn to glycogen and soon run out of glycogen reserves. When their glycogen is used up it takes a couple days to build it back up again and this is why they get "post exertional fatigue" that lasts for a couple days. The capillary hypoperfusion and lack of oxygen can also lead to cognitive dysfunction and constant aching.

If they push themselves they will end up using fat reserves, but if they are leptin resistant, (Also due to the cytokine responses) they won't be able to burn the fatty acids directly. They will then turn to burning protein. These folks will say they are getting fat even though they are eating less and exercising as much as they can.

The person has a low VO2 max on pulmonary stress tests. Many have a VO2 of less than 20 if they are severely ill. The way to correct VO2 max in the CIRS patient is by raising their VEGF level to normal range. Using procrit and VIP can increase the VO2 to 40-50 in a couple weeks.

Normalizing VEGF in CIRS

First realize you would not want to raise VEGF if it is already high. You also would need to discuss this with an oncologist if you are treating a patient who has cancer and CIRS. High VEGF can promote some cancers.

Most research examines lowering VEGF as a treatment for abnormally high VEGF with certain types of cancers. There is an increasing body of research regarding raising VEGF to treat hypoxic brain and cardiovascular issues. There is less information on raising VEGF with nutrients or herbs. I actually suggest you work on lowering TGF beta-1 which will end up helping to lower VEGF. (You may note that many of the herbs and nutrients that lower TGF beta-1 are used to lower VEGF when it is high. Please realize that many of the nutrients and herbs do not act as drugs do. They often have amphoteric activity and may actually cause opposing things to happen in the body at different times.)

High TGF beta-1 will lower VEGF, so one approach is to focus on lowering TGF beta-1 into normal limits. This should also raise the VEGF into normal limits.

 

What will Normalize Low VEGF

Fish Oil

Omega 3 fatty acids 2.4 grams EPA and 1.8 grams DHEA per day. Although there is research showing increased VEGF and angiogenesis in an ischemic condition with an enhanced fish oil diet, there is research showing it lowers VEGF and is antiangiogenic also. This is another situation where we see amphoteric activity.

Low Amylose Diet as created by Dr. Ritchie Shoemaker.

Keeps insulin in control as insulin will increase inflammatory cytokines. Eat at least 6 ounces of protein each day and at least 3 servings of above ground vegetables and fruit every day. No simple sugars, maltodextrins, and corn syrup, no grains such as rice, wheat, rye, barley and oats, no bananas, no underground veggies except onions and garlic, – no nuts other than walnuts and almonds) can eat all fruit except bananas, all above ground veggies and meat.

Scutellaria baicalensis root and Baicalin

Scutellaria baicalensis root and it's constituent called baicalin have been found to raise VEGF expression through the activation of the ERRα pathway. In vitro work, but looks good. Especially interesting when you take into account this herb is used for strokes traditionally.

Although baicalin can induce angiogenesis by stimulating VEGF expression, it has been previously shown to inhibit angiogenesis by suppressing endothelial cell proliferation, migration, and tube formation in vitro, as well as vessel formation in chicken chorioallantoic membrane.This study was focused on the effect of baicalin on endothelial cells, whereas the VEGF study was focused on the effect of baicalin on VEGF expression, a different aspect in regulating angiogenesis. It is possible that baicalin has both pro-angiogenesis (via elevating VEGF expression as shown in one study) and anti-angiogenesis (via suppressing endothelial cell function as shown in this study) activities.

Resveratrol

Resveratrol shows increased VEGF levels in vitro and in vivo (rats). At low dosage (2 ng/mL), resveratrol induces angiogenic actions, whereas at higher dosages (1.2 mg/L), it can inhibit cell survival and angiogenic pathways. Furthermore, pharmacokinetics, bioavailability and metabolism likely play a critical role in appropriate delivery strategies to produce appropriate therapeutic outcomes. Specifically, oral administration leads to rapid absorption to plasma, liver, kidney and heart.

Astragalus

Astragalus has been shown to promote angiogenesis and induces VEGF expression.

Curcumin

Curcumin (From tumeric) Several studies have highlighted the pro-angiogenic properties of curcumin by both oral and topical application. Specifically, serum-free curcumin application showed significant up-regulation of VEGF. Additionally, Kiran and colleagues showed significant capillary network formation in HUVEC and RAEC cultures, vessel sprouting in aortic ring assays, and increased vascular density in CAM assays in response to curcumin treatment. Supplementation of curcumin along with serum caused down-regulation of VEGF. So this suggests a different response depending on extracellular microenvironment.

Erythropoetin

Erythropoetin has been shown in various research to elevate VEGF and Dr. Shoemaker has used Procrit to raise VEGF. Additionally, patients who go to high altitudes will also find it raises their low VEGF levels.

Vasoactive Intestinal Polypeptide(VIP)

Vasoactive Intestinal Polypeptide(VIP) has also been shown to raise VEGF in research by Dr. Ritchie Shoemaker.

Catechins

Catechins such as EGCG have been reported to both inhibit and stimulate VEGF expression.

Quercetin

Quercetin has been shown to induce VEGF expression through increasing HIF-1α expression.

47 crude plant extracts were tested in a CAM assay and in vitro bovine aortic endothelial cell (BAEC) proliferation assays. Of these, 24 demonstrated angiogenic properties with Epimedium sagittatum, Trichosanthes kirilowii and Dalbergia odorifera performing the strongest in both CAM and BAEC models. These may be acting as stimulants to VEGF.

A few more scientific details on VEGF

VEGF expression is induced by growth factors, oncogenes, and hypoxia. The key regulator of VEGF expression in response to hypoxia is hypoxia-inducible factor-1. Levels of HIF-1α expression are determined by the rates of protein synthesis (regulated via an oxygen-independent mechanism) and protein degradation (regulated via an oxygen-dependent mechanism). HIF-1 activates VEGF transcription by binding to the hypoxia response element (HRE) in the VEGF promoter. In addition to HRE, multiple transcription factor-binding sites, including ERR, AP-1, Sp-1, Stat3, and CREB, have been identified within the VEGF promoter.

Studies have found that peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a potent ligand-independent coactivator that interacts with ERRα and also a major regulator of mitochondrial function in response to exercise and other stimuli. Through the activation of ERR-α, PGC-1α has been shown to powerfully induce VEGF expression and angiogenesis in cultured muscle cells and skeletal muscle in vivo, as well as in breast cancer cells, in an HIF-1α independent pathway.

 

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